Hello everyone Frankly, I'm trying to open Excel file(2003) but I get error at Open Function in the below code : (Old Format Or Invalid Library Of kinds (Exception from HRESULT: 0x80028018 (TYPE_E_INVDATAREAD)) Is there anybody can help me? :nonod: where I use the following code. public static Excel.Application ExlApp; public static Excel.Workbook ExlWrkBook; public static Excel.Worksheet ExlWrkSheet; Excel.Application ExcApp = new Excel.Application(); ExcApp.Visible = true; Excel.Workbook excelWorkbook = ExcApp.Workbooks.Open("D:\\Salary Calc.xls", 0, false, 5, "", "", true,Excel.XlPlatform.xlWindows, "\t", true, false, 0, false, true, true); Excel.Sheets ExcSheet = excelWorkbook.Worksheets; string currentSheet = "Sheet1"; Excel.Worksheet excelWorksheet = (Excel.Worksheet)ExcSheet.get_Item(currentSheet); Excel.Range excelCell = (Excel.Range)excelWorksheet.get_Range("A1", "A1");